We contacted the software developer and here is his response. Hope it helps....

The app requires Android 4.3 and that your device support bluetooth 4. If your device has Android 4.3 or higher, but the app does not show up in the Google play store, this means the Google Play store thinks your device isn't compatible (so it's hiding the app). The most likely guess is that the Google Play store thinks your device doesn't have bluetooth 4.

The version of Android 6 that is on your device is software written by Insignia. Sometimes these companies release a software update that isn't quite up to spec, which might cause the Google Play store to decide there is a compatibility issue. Eventually someone complains about the issue, and the company will release a software update. First step is you should check and see if your device has a software update available. Here is a useful article on that:http://e-zapptraincontrol.com/2016/07/06/controlling-e-z-app-trains-with-android/

Locate your product and note the model number (for example: NS-P08A7100). Click through to your product and hit the "contact us" link.

In your communication, I would say "I have the Insignia tablet model XXX running the latest version of Android available (6.0). When I go to the Google Play store, apps that require bluetooth 4 do not display. Can you please verify that my device supports bluetooth 4, and help me figure out how to get that working so apps requiring bluetooth 4 become available in the google Play store?"